564 The American Naturalist. [June, 
the rock as calculated from its analysis is: 23% hornblende, 50% ortho- r 
clase, 16% albite, 8% sodalite, and 3% analcite. 
The Anorthosites of Canada.—The Canadian geologists have 
long considered the Laurentian of northern North America as consist- 
ing of an upper and a lower division, of which the latter rests uncon- 
formably upon the former. This upper division is made up largely of 
basic schists to which the name Novian was given by Hunt. Adams 
has examined all of the important occurrences of the supposed schists, 
and has discovered that in all cases they show an irruptive contact 
with the surrounding gneisses, which they evidently cut. They are 
thus unquestionably post-Laurentian, and, from their relations to the 
overlying rocks, they are thought to be pre-Cambrian. The dark 
rocks are anorthosites—aggregates of plagioclase, with a little pyroxene, 
olivine and some accessories—which are in places schistose, and in 
other places are connected genetically with gabbros. The schistosity 
of the rock is accompanied by the possession of cataclastic structure, 
regarded by the author as due not to dynamic processes, but to the 
movement of the magma just before final consolidation. The plagio- 
clase of the rock which is by far its most prominent component, 18 & 
labradorite so filled with tiny inclusions of microlites, thought by the 
author to be ilmenite tables, that fragments of the mineral are dar 
and often show the play of colors so beautifully seen in the labradorite 
of Labrador. The pyroxenes are a weakly pleochroic green augite, 
and a strongly pleochroic hypersthene. Hornblende, biotite, quartz, 
garnet and zircon are also present in small quantities in all specimens 
of the anorthosite. In the Saguenay river occurrence, olivine E 
enclosed in the plagioclase, and between it and the latter mineral is & 
reaction rim, composed of an inner zone of hypersthene, and an outer 
one of actinolite, including many small, green spinels. All the occur- 
rences of the rock in Canada are briefly described, and with them arè 
compared similar occurrences found elsewhere. 
The Melibocus “ Massiv ” and its Dyke Rocks.—The peak 
of Melibocus’ in the Odenwald consists mainly of a medium- ag 
white granite to the West, and a complex of schists and gneisses t0 p A 
East. The granitic constituents, orthoclase and quartz, are Usua = 
aggregates of small grains variously orientated, and the biotite ge a 
evidence of having been subjected to pressure. Near the contact WE? 
* Neues Jahrb. f. Min., etc., B. B. viii, p. 419. 
3C. Chelius: Notizbl. d. Ver. f. Erdk. z. Darmstadt, 1892, iv, F. 13 H., p.t 
